Sunan An-Nasa'i

It was narrated from Abu Sa'eed Al Khudri that:A man heard another man reciting ""Say: He is Allah, (the) One"" and repeating it. When morning came he went to the Messenger of Allah (ﷺ) and told him about that. The Messenger of Allah (ﷺ) said: ""By the One in Whose Hand is my soul, it is equal to one-third of the Quran